Newport - Three-time champion John Isner rallied to beat Australian Matthew Ebden 4-6, 6-3, 6-4 on Friday and reach the semi-finals of the ATP grass court tournament in Newport, Rhode Island.
Isner, the top seed playing on a wild card invitation as he continues his return from a foot injury, booked a final-four showdown with fourth-seeded Frenchman Ugo Humbert, a 7-5, 3-6, 6-2 winner over Ilya Ivashka of Belarus.
Humbert, 20, is coming off his best performance in a Grand Slam, a run to the fourth round at Wimbledon. He cracked the top 50 in the world rankings this week at No 48.
Isner, 34, was sidelined three months after suffering a stress fracture in his left foot in his loss to Roger Federer in the final at Miami in March.
He missed the French Open and fell in the second round at Wimbledon.
Isner belted 24 aces to overcome Ebden in a rematch of the 2017 Newport final won by the American.
Isner took his record over Ebden to 5-1 as he vies to get his season back on track at Newport - where he also won in 2011 and 2012 - and next week in Atlanta, where he is a five-time champion.
Seventh-seeded Alexander Bublik of Kazakhstan also reached the semi-finals downing American Tennys Sandgren 0-6, 6-3, 6-0.
Bublik, who lost 10 of the last 12 points in the first set but dropped just five points in the third, will face Spain's Marcel Granollers, who completed a rain-disrupted 6-3, 6-0 victory over Germany's Mischa Zverev 6-3, 6-0.
Results on Friday in the ATP tournament at Newport, Rhode Island (x-denotes seeding):
John Isner (USA x1) bt Matthew Ebden (AUS) 4-6, 6-3, 6-4
Ugo Humbert (FRA x4) bt Ilya Ivashka (BLR) 7-5, 3-6, 6-2
Marcel Granollers (ESP) bt Mischa Zverev (GER) 6-3, 6-0
Alexander Bublik (KAZ x7) bt Tennys Sandgren (USA) 0-6, 6-3, 6-0